Aircraft, ships, special-use vehicles, and other vessels may have hatches with hatch doors that may be opened and closed for various uses. For example, a land-based vehicle with a rocket-launch bay may have an external hatch with a movable door that may be opened and closed. As another example, a water vessel may have a missile-launch hatch with a movable hatch door that may open when the missile is to be launched and closed when the missile is to remain in the hatch. Such hatch doors help protect the munitions in the hatch secure from the elements and would-be intruders.
FIG. 1 is a diagram of a conventional vertical launcher system 100, which may be installed in a vessel and which includes a launch cell 110, a hatch door 115 and a hatch-door actuating system 116. When closed, the hatch door 115 (which is shown in an open position in FIG. 1) covers a hold 112 that may be suitable for holding munitions, such as a rocket or missile (not shown). The system 116 may move the hatch door 115 from a closed position (e.g., from a position that covers the hold 112) to an open position (e.g., exposing the hold 112) and vice versa.
Often times, a vessel with such a vertical launch system 100 may be deployed in harsh environments with cold temperatures, and this may result in ice buildup on and around the hatch door 115. If the ice buildup is great enough, the actuation of the hatch door 115 may be compromised. Other environments may cause a buildup of rust that also may prevent the hatch door 115 from actuating properly. Additionally, such a vessel may be the target of intruders and enemies that may wish to obtain the munitions stored in the hold 112. Thus, the system 100 may also include an anti-intrusion mechanism that prevents would-be intruders from externally opening the hatch door 115.
Taking into account the foregoing parameters, the actuating system 116 of the conventional system 100 includes a gear box 130 that drives a linkage system 125 to rotate the hatch door 115 about a trailing edge 120, which is the edge of the hatch door 115 that remains near a plane at the top of the launch cell 110 as the hatch door is actuated. This is in contrast to a hatch door's leading edge 121, which is the end of the hatch door 115 that rotates upward and away from the plane at the top of the hatch 110 when the hatch door is opened
The hatch door 115 may be actuated along a curved path 150 by using the actuating system 116 to rotate the hatch door 115 about the trailing edge 120. The trailing edge 120 of the hatch door 115 is rotatably fixed at this point. Thus, when opening the hatch door 115, the hatch door 115 swings up along the curved path 150 about the rotation point at the trailing edge 120. Likewise, when closing the hatch door 115, the hatch door 115 swings down along the curved path 150 about the rotation point at the trailing edge 120 as well.
Because of the nature of actuating the hatch door 115 at the trailing edge 120, the linkage 125 may not be well suited to provide a rotational moment in a lateral manner. That is, using the conventional actuating system 116 to transfer lateral movement to a rotational moment at the trailing edge 120 is not an efficient use of mechanical advantage. Such conventional mechanisms are not an efficient use of material to handle the aforementioned ice or rust buildup.
Further, the conventional actuator system 116 may employ elaborate system of rockers and cams (not shown in detail) to provide anti-intrusion measures that prevent the hatch door 115 from being pried open externally.